Solar power generation system

Abstract

A solar power generation system includes a string, an inverter, and first and second shut-off devices. The string includes a plurality of solar cell module groups. The first shut-off device cuts off the connections between the plurality of solar cell module groups of a first electric path in response to a first control signal. The second shut-off device cuts off the connections between the plurality of solar cell module groups in a second electric path in response to a second control signal output by a different communication system. The first shut-off device includes a first open-close unit, a first semiconductor switching device connected in series to the first open-close unit and a power supply unit configured to generate power to drive the first open-close unit. The first semiconductor switching device enters an OFF state if the amount of generated power is smaller than a predetermined threshold value.

1 . A solar power generation system, comprising:
 a string including a plurality of solar cell module groups connected in series with each other, the solar cell module groups each including one or more solar cell modules connected in series;   an inverter connected to the string and configured to convert DC power output from the string to AC power;   a first shut-off device connected to a first electric path connecting some of the plurality of solar cell module groups; and   a second shut-off device connected to a second electric path connecting others of the plurality of solar cell module groups different from the plurality of solar cell module groups connected by the first electric path,   wherein   each of the plurality of solar cell module groups in the string each has an open circuit voltage equal to or less than a predetermined open circuit voltage,   the first shut-off device cuts off the connections between said some of the plurality of solar cell module groups connected to the first electric circuit in response to a first control signal from the inverter,   the second shut-off device cuts off the connections between said others of the solar cell module groups connected to the second electric circuit in response to a second control signal output from the first shut-off device by a communication system different from power line communication and sent to the second shut-off device by a a communication line connected between the first shut-off device and the second shut-off device,   the plurality of solar cell module groups in the string includes a first group, and   the first shut-off device includes
 a first open-close unit connected to an anode-side terminal of the first group; 
 a first semiconductor switching device connected in series between the anode-side terminal of the first group and the first open-close unit; and 
 a first power supply unit configured to generate power to drive the first open-close unit, the first power supply unit having an anode-side terminal connected between the anode-side terminal of the first group and the first semiconductor switching device, and a cathode-side terminal connected to a cathode-side terminal of the first group, 
 the first semiconductor switching device being configured to enter an OFF state in a case where an amount of power generated by the first group falls below a predetermined threshold. 
   
     
     
         2 . The solar power generation system according to  claim 1 , wherein the first shut-off device includes a first bypass device that is connected at one end to the cathode-side terminal of the first group and that is connected at another end between the first open-close unit and the first semiconductor switching element. 
     
     
         3 . The solar power generation system according to  claim 1 , wherein the first semiconductor switching device is a MOSFET device or an IGBT device. 
     
     
         4 . The solar power generation system according to  claim 1 , wherein the first shut-off device includes a second open-close unit connected to the cathode-side terminal of the first group. 
     
     
         5 . The solar power generation system according to  claim 4 , wherein the second open-close unit is driven by the power supplied from the first power supply unit. 
     
     
         6 . The solar power generation system according to  claim 4 , wherein the first shut-off device is configured to control the opening and closing of the first open-close unit and the second open-close unit independently of each other. 
     
     
         7 . The solar power generation system according to  claim 1 , wherein the plurality of solar cell module groups in the string includes a second group, and
 the second shut-off device includes
 a third open-close unit connected to an anode-side terminal of the second group; 
 a second semiconductor switching device connected in series between the anode-side terminal of the second group and the third open-close unit, and 
 a second power supply unit configured to generate power to drive the third open-close unit, the second power supply unit having an anode-side terminal connected between the anode-side terminal of the second group the second semiconductor switching device, and a cathode-side terminal connected to a cathode-side terminal of the second group, 
 the second semiconductor switching device being configured to enter an OFF state in a case where the amount of power generated by the second group falls below a predetermined threshold. 
   
     
     
         8 . The solar power generation system according to  claim 7 , wherein the second shut-off device includes a second bypass device, the second bypass device being connected at one end to the cathode-side terminal of the second group and being connected at another end between the third open-close unit and the second semiconductor switching element. 
     
     
         9 . The solar power generation system according to  claim 7 , wherein the second semiconductor switching device is a MOSFET device or an IGBT device. 
     
     
         10 . The solar power generation system according to  claim 7 , wherein the second shut-off device includes a fourth open-close unit connected to the cathode-side terminal of the second group. 
     
     
         11 . The solar power generation system according to  claim 10 , wherein the fourth open-close unit is driven by the power supplied from the second power supply unit. 
     
     
         12 . The solar power generation system according to  claim 10 , wherein the second shut-off device is configured to control the opening and closing of the third open-close unit and the fourth open-close unit independently of each other. 
     
     
         13 . The solar power generation system according to  claim 1 , wherein the first shut-off device cuts off the connection between the plurality of solar cell module groups connected to the first electric path in response to the first control signal from the inverter and then outputs the second control signal to the second shut-off device. 
     
     
         14 . The solar power generation system according to  claim 1 , wherein each of the plurality of solar cell module groups in the string has an open circuit voltage of 165 V or less. 
     
     
         15 . The solar power generation system according to  claim 1 , wherein the inverter outputs the first control signal to the first shut-off device by power line communication. 
     
     
         16 . The solar power generation system according to  claim 1 , wherein the inverter outputs the first control signal to the first shut-off device by wireless communication. 
     
     
         17 . The solar power generation system according to  claim 1 , wherein at least one of the plurality of solar cell module groups in the string includes a plurality of solar cell modules connected in series.